When I go to my server with ?hidden=1 added, I see the list of locations. So locations.ini is loaded properly.

But, I think the agents are not communicating to the server. Now, I've read a lot of threads where people post their wptdriver.ini. But I can't find them when I browse through the folders of the agents (via SSH, these are also on the GCE).

The main issue I have seen is that sometimes the auto-generated server name doesn't work. If you replace the server name in the wpt_server= part of the string with the private IP address of the instance (10.x.x.x) that usually clears it up.

The agents will also normally auto-identify their location based on the region they are running in so you can use a single template across all regions. If you want to use specific location ID's you can set up a template for each region and add wpt_loc= with the appropriate location ID (and the key).

The main issue I have seen is that sometimes the auto-generated server name doesn't work. If you replace the server name in the wpt_server= part of the string with the private IP address of the instance (10.x.x.x) that usually clears it up.

The agents will also normally auto-identify their location based on the region they are running in so you can use a single template across all regions. If you want to use specific location ID's you can set up a template for each region and add wpt_loc= with the appropriate location ID (and the key).

Awesome! This worked. I changed the wpt_server to the ip address of the server and now I'm able to connect the agents.

For future reference, editing an agent doesn't work for long. You have to run the template again and add the ip of the server there during installing the template.

How did Google steal 30 hours of your life? WebPageTest isn't a Google product. When I worked for them they did contribute dev resources to work on it from time to time but that's about it.

The project is open source and isn't abandoned but there also isn't some sort of big team or company behind it supporting it. I work on it in my spare time and don't have time to remotely diagnose every install.

If you're looking for something with better support I STRONGLY recommend you invest in a commercial service like SpeedCurve, Catchpoint or Calibre. Otherwise the trade-off for open source is your time (and the 30 hours you spent getting it up is likely just the tip of the iceberg).

No, not Webpagetest. GCP. I am seeing several zones that are troublesome, and that was one of them. Sorry - should have been more specific in my complaining.
And SpeedCurve is awesome - I have that implemented on all of my projects.